<div class="problemindexholder" problemindex="A">
 <div class="ttypography">
  <div class="problem-statement">
   <div class="header">
    <div class="title">
     A. Alex and broken contest
    </div>
    <div class="time-limit">
     <div class="property-title">
      time limit per test
     </div>
     2 seconds
    </div>
    <div class="memory-limit">
     <div class="property-title">
      memory limit per test
     </div>
     256 megabytes
    </div>
    <div class="input-file">
     <div class="property-title">
      input
     </div>
     standard input
    </div>
    <div class="output-file">
     <div class="property-title">
      output
     </div>
     standard output
    </div>
   </div>
   <div>
    <p>
     One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problems were saved, but now he needs to find them among other problems.
    </p>
    <p>
     But there are too many problems, to do it manually. Alex asks you to write a program, which will determine if a problem is from this contest by its name.
    </p>
    <p>
     It is known, that problem is from this contest if and only if its name contains one of Alex's friends' name
     <span class="tex-font-style-bf">
      exactly once
     </span>
     . His friends' names are "
     <span class="tex-font-style-tt">
      Danil
     </span>
     ", "
     <span class="tex-font-style-tt">
      Olya
     </span>
     ", "
     <span class="tex-font-style-tt">
      Slava
     </span>
     ", "
     <span class="tex-font-style-tt">
      Ann
     </span>
     " and "
     <span class="tex-font-style-tt">
      Nikita
     </span>
     ".
    </p>
    <p>
     <span class="tex-font-style-bf">
      Names are case sensitive.
     </span>
    </p>
   </div>
   <div class="input-specification">
    <div class="section-title">
     Input
    </div>
    <p>
     The only line contains string from lowercase and uppercase letters and "
     <span class="tex-font-style-tt">
      _
     </span>
     " symbols of length, not more than
     <span class="tex-span">
      100
     </span>
     — the name of the problem.
    </p>
   </div>
   <div class="output-specification">
    <div class="section-title">
     Output
    </div>
    <p>
     Print "
     <span class="tex-font-style-tt">
      YES
     </span>
     ", if problem is from this contest, and "
     <span class="tex-font-style-tt">
      NO
     </span>
     " otherwise.
    </p>
   </div>
   <div class="sample-tests">
    <div class="section-title">
     Examples
    </div>
    <div class="sample-test">
     <div class="input">
      <div class="title">
       Input
      </div>
      <pre>Alex_and_broken_contest<br/></pre>
     </div>
     <div class="output">
      <div class="title">
       Output
      </div>
      <pre>NO</pre>
     </div>
     <div class="input">
      <div class="title">
       Input
      </div>
      <pre>NikitaAndString<br/></pre>
     </div>
     <div class="output">
      <div class="title">
       Output
      </div>
      <pre>YES</pre>
     </div>
     <div class="input">
      <div class="title">
       Input
      </div>
      <pre>Danil_and_Olya<br/></pre>
     </div>
     <div class="output">
      <div class="title">
       Output
      </div>
      <pre>NO</pre>
     </div>
    </div>
   </div>
  </div>
  <p>
  </p>
 </div>
</div>
